Variation in early growth of black cottonwood clones in the Willamette Valley

Description:

Black cottonwood (Populus trichocarpa Torr. & Gray) cuttings were collected from five Oregon provenances along a north-south gradient. Cuttings from each provenance were grown for 1 year at two locations, one on the Willamette Valley floor and the other on the Valley margin. Survival at both locations was poor. Stem production was greater on the floor site than the margin site because of differences in edaphic conditions and deer browsing at the margin site. Variation in stem production was greater within than among provenances, suggesting that single-tree selection would be more profitable than provenance selection. Leaf length and width measurements were highly correlated with stem weight and were chosen as the best method for nondestructive selection of superior juvenile individuals; however, as trees grow older, stem volume may be a better indicator. Suggestions for cottonwood culture in western Oregon are discussed.[Page 22 is a blank page.]